1. Field of the Invention
The present invention relates to silk screening printing. More particularly, the present invention relates to devices for properly measuring and aligning screen printed images. Additionally, the present invention relates to measurement device that can indicate an offset relationship between screen printed images.
2. Description of Related Art
Including Information Disclosed Under 37 CFR 1.97 and 37 CFR 1.98.
Indicia applied permanently to articles of clothing and other textiles have become very popular. Fanciful indicia, such as logos, slogans, college names, sports team names and sayings, are now commonplace. As a result, screen printing has become very popular. Large commercial operations that screen print textiles are common today.
Indicia can be one or more colors. Typically, a screen printing machine has at least one station for each color employed. For example, a design incorporating two colors will have at least two printing stations, one for each color. A design employing eight colors will have at least eight stations. Each station generally includes a printing head, which supports a single screen, the ink to be used at that station and a mechanism for applying the ink to the textile. Each color is carried by a single screen. The textile to be screened travels from printing station to printing station by one of a number of methods, such as a chain or a rigid arm. The textile is usually carried by a metal pallet, pallet support, flat bed, or platen. Common printing machines include turret, oval and linear. In addition to printing stations, there are may also be curing stations to heat and set the inks placed on the textile or substrate. Because of the intricacies and the numerous colors involved in more recent designs, registration and indexing of the textiles from station-to-station have become crucial requiring exacting tolerances. Accordingly, attention is mandatory to these aspects of the screen printing process. Registration and complete accuracy are further demanded in the process leading up to printing the final product.
It is necessary to preposition, or align the screens before printing, so that, when each screen sequentially prints its portion of the composite print graphic, the images are in the approximate exact positions to accurately reproduce and reflect the original artwork. This process of prepositioning or aligning multiple screens is called “registering”, and before any production run utilizing multiple screens can begin, all of the screens must be “registered” to ensure the proper fit of colors. Some designs may require colors to be separated by a required distance, while others may require colors to be aligned edge-to-edge with no separations. If accurate registration is not accomplished, colors may overlap and “bleed” into one another, or alternatively, be separated when they should be touching. Prints that are “out of register” may be blurry, inaccurate and generally inconsistent with the original artwork.
Since all of the screens have to be placed in the printing machine and in the proper place in relation to the other colors, the screens are placed in the printing machine as close to alignment as possible either by eye or using a device similar to an early invention by the present inventor (identified in U.S. Pat. No. 6,101,938). After the first test print, if the color are not in correct alignment, it is necessary to measure how far the color is off-location or “not in registration”. As such, the user of the printing machine will move the screen over a small amount and test print again and measure again. This trial-and-error process is very time consuming and often results in inaccurate positioning. As such, a need has developed in which to provide a measurement device so that the operator of the screen printing machine can properly align the various colors as close as possible on the machine.
In the past, various patents have issued relating to screen printing machines and registration processes. For example, U.S. Pat. No. 6,101,938, issued on Aug. 15, 2000 to the present inventor, describes a system for accurately registering multiple silkscreens relative to a printing surface after they have been clamped into a silkscreen holder of a printing head of a rotary screen printing machine. A generally L-shaped registration device attached adjacent to one side of a pallet of the printing machine has first and second sides orthogonal relative to each other with a pair of gauges having visual displays positioned on the first side and a third gauge positioned on the second side. The gauges have outwardly-biased plungers controlled by a lever to be simultaneously moved between a retracted positioned, a free-floating position and an engaged position relative to respective first and second sides of a silkscreen frame. The gauge displays allow the operator to take numerical readings to determine if, and how much, a frame has shifted from a zero setting after being clamped in the frame holder. It also indicates which frame has shifted and allows one to quickly re-register a frame to its previous setting. The gauge also compensates for frames having misaligned images.
U.S. Pat. No. 3,513,775, issued on May 26, 1970 to L. D. Guthrie, describes a process for registration and silk screening both sides of a sheet. Registrations bars are accurately located relative to the printing surface and the silk screen equipment. The sheet material to be printed remains attached at one edge thereof to a registration bar for printing first on one side and then on the other. The material is progressively laid on the printing surface by gradually withdrawing a support from the underside of the material.
U.S. Pat. No. 4,091,726, issued on May 30, 1978 to H. R. Walker, shows a magnetic registration apparatus for a silk screen printer. This apparatus includes a carriage for rotatably supporting the articles with respect to the longitudinal axis thereof and magnetic means on the carriage for drawing a magnetically attractable index on the article. As such, a surface on the article is oriented in a predetermined disposition with a pattern in the silk screen stencil. The carriage is adapted to lift the articles from a high speed conveyor into contact with the silk screen stencil.
U.S. Pat. No. 4,493,254, issued on Jan. 15, 1985 to Landesman et al., teaches a silk screen printing machine and drive system. This screen printing machine has a carousel rotatable about a central support and carries a circular arrangement of work-receiving tables. A rotation of the carousel causes the work-receiving tables to come into registry with corresponding printing units for screen printing of work carried by the work-receiving tables.
U.S. Pat. No. 5,613,436, issued on Mar. 25, 1997 to Taylor, describes a variable position pin registration plate for multicolor silk screen printing. The plate assembly includes an apparel support platen mounted on an elongated support arm and at least one pivoting silk screen frame support assembly movably supporting a silk screen frame above the apparel support platen. The registration plate assembly comprises a flat plate portion having a plurality of pairs of spaced vertical bores therethrough and a pair of pins each extending upwardly from the plate portion through one of the bores and adjustably secured in the bore. The pair of pins fit into correspondingly spaced holes in the rear side of the silk screen frame to provide final alignment of the frame on the apparel support platen as the frame is lowered into position.
U.S. Pat. No. 5,664,495, issued on Sep. 9, 1997 to R. B. Winter, shows a print screen alignment system for registering printing screens. This system includes a plurality of outwardly projecting electrical switches. The switches are positioned to engage a first side of a screen frame and positioned to engage a second side of the screen frame. The first and second sides of the frame are orthogonal relative to each other. A pair of lights are activated by engagement of the frame with the switches. Both of the lights being activated by simultaneous engagement of each of the switches by a screen frame. Similar sets of switches are provided on a table that supports the screens during exposure to an image to be replicated during printing and on a device that temporarily replaces a printing platen for alignment of each screen in a multi screen printing device.
U.S. Pat. No. 5,718,057, issued on Feb. 17, 1998 to Rosli et al., provides a register draw-in device for sheet printing and embossing machines. This device has two front or leading edge stops and a side stop. Position sensors detect print marks of a sheet. Two detectors associated with the front stops detect the sheet leading edge. The front stops are adjustable by control elements until front print marks on the sheet are detected by sensors. A control element then adjusts the side stop until a side print mark is detected by another sensor. A system control controls this register correction with the position sensors, the detectors and the control elements
U.S. Pat. No. 5,953,987, issued on Sep. 21, 1999 to A. L. Oleson, provides a screen printing registration system. This system has an exposure frame and a registration printing pallet for registering a printing screen frame holding a screen first to the artwork and next to the pallet support the product to be screened.
U.S. Pat. No. 6,691,616, issued on Feb. 17, 2004 to T. Wolf, describes a device for detecting the position of a printing plate on a cylinder of a rotary printing machine. This device has register equipment corresponding with an edge of the printing plate. There is at least one mechanical stress sensor assigned to the register equipment. The mechanical stress sensor is a piezoelectric force sensor.
U.S. Pat. No. 6,038,977, issued on Mar. 21, 2000 to Haney et al., provides a multiple printing process registration method. A first image is printed a substrate at a first location different from a location of the digital printer. A template is mounted on the digital printer. The digital printer is used to print a second image on the template. The substrate is placed on the digital printer with respect to template. The first image on the substrate is aligned with the second image on the template. The substrate is secured on the digital printer at a location where the first image on the substrate aligns with the second image on the template. The digital printer can then be used to print the second image on the substrate in alignment with the first image.
It is an object of the present invention to provide a measuring device so as to allow the operator of a screen printing machine to properly align images.
It is another object of the present invention to provide a measurement device that allows accurate measurement to be taken of any offset or undesired misalignment of one color image with respect to another color image.
It is another object of the present invention to provide a measurement device that provides a numerical indicia relative to an offset relationship between the screen printed images.
It is still a further object of the present invention to provide a measurement device that facilitates the accurate printing of multi-color silk screen images.
It is still a further object of the present invention to provide a measurement device that minimizes the labor requirements and trial-and-error efforts in order to achieve a proper silk screened printed image.
These and other objects and advantages of the present invention will become apparent from a reading of the attached specification and appended claims.